Circuit interrupter having uniformly spaced spiral arc runners in a confined atmosphere for improved arc voltage control



1964 'r. J. SCULLY ETAL 3,156,303

CIRCUIT INTERRUPTER HAVING UNIFORMLY SPACED SPIRAL ARC RUNNERS IN ACQNFINED ATMOSPHERE FOR IMPROVED ARC VOLTAGE CONTROL Filed May 29, 19622 Sheets-Sheet l F/GJ. F762.

.THoMAs J ScuLLY, V/NCENT N. STEWART,

5y W s.

ATTORNEY- Nov. 10, 1964 T. J. SCULLY ETAL 3,156,803

CIRCUIT INTERRUPTER HAVING UNIFORMLY SPACED SPIRAL ARC RUNNERS IN ACONFINED ATMOSPHERE FOR IMPROVED ARC VOLTAGE CONTROL.

2 Sheets-Sheet 2 Filed May 29, 1962 E c M F v m .fl w u Y RCE E N m VS TNAT,A M & 5 H Tm V United States Patent CIRCUIT INTERRUPTER HAVINGUNIlFORMLY SPACED SPIRAL ARC RUNNERS [N A CUN- FINED ATMOSPHERE FORIMPROVED ARC VOLTAGE CONTROL Thomas J. Scully, King of Prussia, andVincent N. Stewart, Springfield, Pa., assignors to General ElectricCompany, a corporation of New York Filed May 29, 1962, Ser. No. 198,64719 Claims. (Cl. 200-144) The present invention relates to a circuitinterrupter and more particularly to a circuit interrupter forextinguishing a developed arc wherein the interrupter has switchcontacts and are runner members disposed in a container.

In the past, circuit interrupter switch contacts have been enclosedwithin a suitable container or envelope having an atmosphere therein,which may be hydrogen gas or the like. The gas within the container mayhave a pressure less than atmospheric, equal to atmospheric, or greaterthan atmospheric. Hydrogen gas is particularly desirable because of itshigh dielectric strength which prevents the reforming of a developedelectric are after the arc has been drawn in the presence of thehydrogen gas and extinguished. The non-oxidizing atmosphere that resultsfrom using hydrogen gas substantially reduces deterioration or pittingof the switch contact-s and helps maintain the switch contact surfacesin a clean and bright condition, thereby improving performance and lifeof the circuit interrupter. A further advantage of hydrogen gasatmosphere is that it exhibits good heat conductivity and a highdiffusion capacity while at the same time providing for isolation offlash and noise that will develop when the arc is interrupted.

During the circuit interrupting process, the roots or terminals of theare developed upon separation of the switch contacts are likely toproduce extreme local heating and increased ionization if the arc shouldstall or remain immobile. Having only an atmosphere in the enclosure(for example, hydrogen gas) to extinguish the developed arc does notcompletely solve the existing problem of eliminating hot spots or arespots on the switch contacts that are caused by the roots or terminalsof the developed arc. It is desirable to have the developed arc movecontinuously in an efiort to eliminate these hot spotsl In the past thishas been done by setting up a magnetic field to exert a force whichtends to cause the developed arc to move, and if the magnetic forcefield is sufficient, the developed arc will be caused to moveunhaltingly until extinguished. Such movement of the arc will thusminimize the erosion or deterioration of the contacts. If such amagnetic force field is present to move the developed arc, then suitablearc runner means should be provided adjacent to the switch contacts toreceive the developed arc so that the arc may run its course until it isextinguished.

It is desirable to control the developed are so as to maintain arcvoltage, within predetermined maximum and minimum limits. The arcvoltage must be high enough so that the system in which the circuitinterrupter is utilized cannot sustain the developed are for a prolongedperiod of time; if the arc voltage were lower than system voltage, thedeveloped are might not be extinguished in a reasonably short period oftime. Yet the arc voltage must not be so high that the voltage peakexceeds the insulation level of the system. This is especially true atthe moment of extinction of the developed arc. Should the arc voltageexceed the insulation level of the system, other electrical apparatusand elements that are connected to the circuit might suffer damage.Obtaining arc voltage control in an enclosed gas interrupter dependsupon a combination of at least three inter-related factors: (1) initialgas pressure, (2) length of the arc, and (3) the amount of stored energyof the system in which the circuit interrupter is utilized. If the pathand velocity of the respective roots or terminals of the arc weresuitably controlled so as to maintain the .arc moving at a substantiallyconstant velocity and with a near constant arc length, not only couldundesirable voltage fluctuations be avoided and the enveloping gas bemost etficiently utilized, but in addition the deterioration of theswitch contacts and the arc runner means could be minimized. This wouldimprove performance and extend the usable life of the circuitinterrupter without requiring expensive periodic maintenance orstructural repairs or replacements.

Accordingly, it is a principal object of the invention to provide a gascircuit interrupter having improved arc extinguishing means.

Another object of the invention is to provide a gas circuit interrupterhaving improved arc extinguishing means including means to move the arebeing extinguished.

A further object of the invention is to provide a gas circuitinterrupter having improved arc extinguishing means adapted to develop amagnetic force field by a structural arrangement that is compact yeteffective to continuously move the are along opposing electrodes or arcrunners until the arc is extinguished.

Likewise, it is an object of the invention to provide a new and improvedcircuit interrupter having an arc extinguishing means that maintains adeveloped are at a near constant arc length between predeterminedminimum and maximum arc voltage limits while the arc is being moved andextinguished.

An additional object of the invention is to provide an improved andcompact circuit interrupter having arc extinguishing means suitable forinterrupting either AC. or DC. electric power.

Briefly, in accordance with one embodiment of the invention, a circuitinterrupter is provided having a pair of separable electrical contactspositioned within a tank containing an atmosphere, which is preferablyhydrogen gas. A pair of opposed and equally spaced arc runners of nearlyclosed spiral configuration are provided, with one of the arc runnersbeing electrically connected to one of the interrupter contacts andother runner being associated with the other contact. An electric arcwill be developed upon separation of the contacts, and it is caused tomove through the controlled gap between the parallel arc runners byinteraction with the magnetic field that is produced by current flowingin the runners. The are plasma in this field experiences a translationalforce which propels it orbitally along the runners until it isextinguished by the action of the gas within the tank, and while movingin this manner the arc is confined by the tank wall which is generallyconcentric with the spiral arc runners.

While the specification concludes with claims particu larly pointing outand distinctly claiming the subject matter which may be regarded as theinvention, the organization and method of operation together withfurther objects and advantages thereof may best be understood byreference to the following description which is taken in connection withthe accompanying drawings, in which:

FIG. 1 is a front view of the circuit interrupter having a portion ofthe tank wall broken away to expose the internal components of theinterrupter;

FIG. 2 is a view of the circuit interrupter of FIG. 1 having broken awayportions of the internal structural components to show the relativepositions of the components within the tank;

FIG. 3 is an enlarged fragmentary view of the circuit interrupter innercomponents on the line 3-3 of FIG. 1 in the direction of the arrows, andshowing particularly the structural components of the lower portion ofthe circuit interrupter;

FIG. 4 is an enlarged fragmentary view of the inner components on theline 44 of FIG. 1 in the direction of the arrows and showingparticularly the structural components of the upper portion of thecircuit interrupter;

FIG. 5 is a schematic view illustrating the relation between a currentflow through the pair of arc runners and the direction of movement of adeveloped are maintained the-rebetween;

FIG. 6 is a view of a modification of the circuit interrupter of theinvention with broken away portions of the inner structural componentsto show the relative positions of the modified components within thetank in a circuit breaking position;

FIG. 7 is a view of the modification of FIG. 6 to show the relativepositions of the modified components within the tank in a circuit makingposition; and

FIG. 8 is a fragmentary schematic view of yet another modification ofthe circuit interrupter of the invention showing the mechanical andelectrical arrangement of the inner structural components within thetank.

Referring to the drawings, and particularly to FIG. 1 and FIG. 2, thecircuit interrupter of the invention comprises a generally cylindricalcontainer or tank 1 that has an atmosphere therein to extinguish adeveloped arc. Such an atmosphere as hydrogen gas when confined withinthe circuit interrupter tank 1 will exhibit an increase in pressureduring the extinguishing of a developed arc since the arc heats the gas.Obviously then, the tank 1 has walls of sufiicient thickness to safelycontain the pressurized gas therein. As indicated, the atmosphere ispreferably hydrogen gas but may be any other gas or atmospheric mixturethat exhibits desired characteristics for extinguishing a developed arc.

Line terminals 2 and 3, which are adapted for connection to an externalelectric power circuit (not shown), enter the tank 1 through its topwall and extend interiorly in parallel, generally axial directions. Theline terminals 2 and 3 are electroconductive members and are insulatedfrom the tank 1 by the respective seals and insulator bushings 4 and 5.Line terminal 2 extends inwardly into the tank 1 and terminates in afixed or stationary contact 6. Similarly, line terminal 3 extendsinwardly into the tank 1 to terminate in a fixed or stationary contact7.

The stationary contacts 6 and 7, in the preferred embodi- 13 thatextends through a metallic bellows seal 14 having a conventional form.The bridging contact 10' which is fastened to the shaft 13 by means ofthe pin shown in FIGS. 2 and 3 may be suitably insulated from theoperating shaft 13 and the tubular bellows 14 to prevent an undesirablecurrent flow therethrough. The shaft 13 will move the bridging contactit normal to the plane of the stationary contacts 6 and 7 into or out ofsubstantially simultaneous engagement with both contacts 6 and 7. Thus,circuit control of the respective line terminals 2 and 3 is maintained.

A liner member 15 that is formed from suitable insula'ting material maybe inserted in the tank 1 adjacent to an inner wall thereof to encirclethe arc runners l7 and 22. As shown it is disposed in concentricrelation- 4 wall of the tank and the previously mentioned contacts andany electric arcs that may be developed during operation of the circuitbreaker as will be described.

An upper spiral arc runner 17, most clearly shown by FIGS. 1, 2 and 4,is located within the tank 1 slightly above and adjacent to thestationary contacts 6 and 7. As is best seen in FIG. 4, the arc runner17 comprises an elongated, generally circular member whose opposite endsare spaced from each other by a relatively short gap 17a. This memberand the circular cross section of the tank 1 are substantiallyconcentric with each other. The spiral arc runner is in electricalcontinuity with the first stationary contact 6 by means of an inclinedbar 18 of electrically conductive material that is appended to member 17at its inner end. The are runner is suitably supported and insulatedfrom the tank by insulator support assemblies 19 and 20.

A lower spiral arc runner 22, best shown by FIGS. 1, 2 and 3, is spacedfrom and generally surrounds the movable bridging contact 10. As is bestseen in FIG. 3, the arc runner 22 also comprises an elongated, generallycircular member having opposite ends spaced from each other by arelatively short gap 22a, and it too is disposed in substantiallyconcentric relationship with a circular cross section of the tank 1.This spiral arc runner is maintained in electrical continuity with thesecond stationary contact 7 by an inclined bar 23 that is appended tomember 22 at its inner end, while it is electrically insulated from themetallic tank 1 by a suitable insulator support assembly 24.

The upper spiral arc runner 17 and the opposing lower spiral arc runner22 are fixedly positioned with the tank 1 in spaced-apart parallelplanes which are parallel to but on opposite sides of the plane of thestationary contacts 6 and 7. The are runners are equidistantly spacedfrom each other. The desired dimension of this spacing may be determinedand maintained by the inclination and length of the respective inclinedbars 18 and 23 and by the insulator spacer posts 26 and 27 that arepositioned between the upper spiral arcrunner 17 and the lower spiralarc runner 22. The short gaps 17a and 22a between the overlapping endsof the respective runners are out of register, and in the illustratedstructure they are located diametrically opposite one another. Both theupper spiral arc runner 17 and the lower spiral arc runner 22 curl inagreement with each other.

The electrically conductive movable bridging contact 10 as shown byFIGS. 2 and 3 can be formed into ablade element such as shown. However,since it is desired to reduce surface pitting at the points whereinitial arcs may be developed, upwardly extending contacttips 11 and 12that are formed from a metal which resists pitting are positionedv onthe blade element to separably engage the first and second stationarycontacts 6 and 7 'respectively. Contacts 6 and 7 may be formed fromasimilar metal which resists pitting.

Operatively, a line current passes through the circuit interrupter ofthe invention when the movable bridging contact 10 is positioned in thetank 1 to engage the respective contact tips 11 and 12 with thestationary electrical contacts 6 and 7. The direction of a line currentflow through the circuit interrupter is not critical in the inventionsince the circuit interrupter has applicability to either A.C. or DC.voltages. This will be subsequently described in more detail. When themovable bridging contact ltl separates from the stationary contacts 6and 7, it moves in a plane normal to the plane of the stationarycontacts. As a result of this movement, at least two arcs are drawnbetween the respectivecontact tips 11 and 12 of the bridging contact 10and, the stationary contacts 6 and 7. These arcs are indicated in 7 FIG.2 by the letters A and B. As the movable bridging contact 10 is movedprogressively. away from the statlonary contacts 6 and 7, the developedarcs at A and B Wlil. move radially outwardly to the respectiveintermediate locations at C and D. The upper roots or terminals 30 and31 of the developed arcs at the intermediate points C and D are inengagement with the first inclined bar 18 and the second inclined bar23. The lower terminals 32 and 33 of the arcs at the intermediate pointsC and D are in engagement with the peripheral surface of the movablebridging contact 10.

The arcs at the intermediate points C and D have traveled radiallyoutwardly from the initial positions at A and B since, when the contactsare separated to form the arcs, the magnetic efiect of the arcs or loopswill impel the arcs radially outwardly toward the are running surfacessuch as the spiral arc runners 17 and 22 of the invention. The speed atwhich the arcs or loops move radially outwardly toward the arc runningsurfaces depends upon the magnitude of the arcing current and varies asa function of this arcing current. In other words, arcs of relativelyhigh current magnitude move rapidly outwardly toward the are runningsurfaces whereas arcs of relatively low current magnitude move atconsiderably lesser speeds than the high current arcs. In accordancewith the invention, as the arcs continue to move outwardly from theintermediate positions at C and D, are C eventually reaches a positionwhere it touches the lower spiral arc runner 22, and the arc designatedas E is formed. The are D will be extinguished at this time since thearc current now reaches the inclined bar member 23 directly through therunner 22 which is conductively connected to the inclined bar 23. Thus,in the course of a circuit interruption, the developed arcs at initialpositions A and B become the single are at position E that is nowlocated with its upper terminal 30 engaging the upper spiral arc runner17 and its lower terminal 32 engaging the lower spiral arc runner 22 tomaintain current through the circuit interrupter. At this point, inaccordance with the structural arrangement of the invention, a magneticforce due to arc current flow is exerted upon the developed arc E tomove it along and between the spiral arc runners 17 and 22 in an orbitalfashion.

Referring now to FIG. 5, the magnetic forces developed by the flow ofcurrent through the internal components of the circuit interrupter ofthe invention are illustrated. These magnetic forces act to advance orpropel the developed arc E in a clockwise direction between the spiralarc runners 17 and 22. The current flowing in the upper spiral arcrunner 17 from the first stationary electrical contact 6 to the upperterminal 30 of the developed arc E produce the magnetic lines of force40. The are current flow in the developed are E forms the magnetic linesof force 41. Current returns through the lower spiral arc runner member22 to the second stationary electrical contact 7 from the lower terminal32 of the developed are E and produces magnetic lines of force 42. Itshould be noted in FIG. 5 that the magnetic lines of force 40 and 42 actin the same direction between the upper spiral arc runner 17 and thelower spiral arc runner 22. This additive effect will substantiallyincrease the intensity of the magnetic field between the spiral arcrunners 17 and 22 on the left side of the developed are E which iscommon to the arc current flow through the spiral arc runners. Themagnetic lines of force 41 of the developed are E also increase theintensity of the magnetic field that is developed between the spiral arcrunners 17 and 22. N0 arc current flows in the spiral runners 17 and 22on the right side of the are E so that the only magnetic field on thatside of the are E is from the previously described magnetic lines offorce 41.

The interaction of these previously described magnetic fields and thearc plasma E produces a net tangential force that acts upon thedeveloped arc and drives the are E clockwise, i.e., from left to rightin FIG. 5. The motion of the arc E during this clockwise circulationexhibits a constant rate of tangential movement and generates a paththat defines the lateral area of a cylinder. This constant'rate oftangential movement by the are E drives the are into fresh or unusedareas of atmosphere within the tank 1 to efliciently utilize theextinguishing ability of a particular gas or atmospheric mixture withinthe tank.

Although not shown, when an arc current flows through the spiral arerunners 17 and 22 in a direction opposite from that shown by FIG. 5,i.e., from runner 22 to runner 17, the net tangential force that willact upon the developed are B will still drive the arc in a clockwisedirection. The magnetic fields relating to the are or loop will stilldevelop a net tangential force on the same side of the are E aspreviously described and illustrated by FIG. 5. Thus a developed are Eof either AC. or DC. current flow will always move in a clockwise direction because of the particular mechanical arrangement of the spiral arcrunners 17 and 22 as shown in one embodiment of the invention by FIGS.l-4. The direction of movement of the developed arc, i.e., clockwise orcounterclockwise, is therefore dependent upon the mechanical arrangementof the spiral arc runners 17 and 22 rather than upon the direction ofthe arc current which flows therethrough. If the direction of spiralcurl of the arc runner members 17 and 22 is reversed, a developed aresuch as are E will move in a counterclockwise direction since themagnetic fields would then be on the right side of the are rather thanon the left side such as shown by FIG. 5.

Referring again to FIGS. 2 and 3, the circuit interrupter of theinvention provides that the gaps 17a and 22a in the respective spiralarc runners 17 and 22 are out of register. Therefore, when the developedare E has moved through a first predetermined portion of its orbit, theconstant rate of tangential movement of the are E will cause the lowerterminal 32 to jump the gap 22a in the lower arc runner 22. After theare E has been propelled in a clockwise direction through the remainderof its orbit, the upper terminal 30 of the arc E reaches the outer endof the upper arc runner 17 whereupon the upper terminal 30 of the are Ejumps gap 17a. It can readily be seen that one terminal of the developedarc continues to engage a spiral are runner Whenever the oppositeterminal of the arc is jumping a gap in the associated arc runnermember. The constant rate of tangential movement of the developed arc inconjunction with the angularly displaced gaps of the spiral arc runnersin the circuit interrupter of the invention result in unhalting movementof the are into fresh gas at a substantially constant rate, whereby theextinguishing ability of the gas is most efiiciently utilized. Both ofthese features as realized by the invention contribute to minimizing thepossibility of the developed arc E stalling between the opposed spiralarc runner members 17 and 22. The continuous movement of the are Eprevents significant erosion of arc runner material which would occur ata stalling point. The developed are E continues to circulate within thetank 1 under the tangential force between the spiral are runners 17 and22 for a length of time and for a total distance that are both dependentupon the amount of available energy that must be expended in order toextinguish the arc.

During the clockwise circulation or orbital movement of the developedare E in the structural arrangement of the invention as shown by FIGS.l-4, the cylindrical walls of the tank 1 confine the arc and limit itsmaximum length. The maximum spacing between the spiral arc runners 17and 22 and the concentric inner wall of the tank 1 is dependent upon themaximum arc voltage permissible. The insulating liner 15 may be providedto prevent the possibility that the developed are E might jump or are tothe inner wall of the metallic tank 1. In the embodiment as shown byFIGS. 1 through 4, we contemplate a dead tank and such jumping or arcingof the arc E to the inner wall of the metallic tank 1 is not desired. Insome applications of the circuit inter- Z rupter of the invention,however, the design parameters of the tank and the previously describedinner structural components may eliminate the need for the insulatingliner 15 while still obtaining the proper functioning of the circuitinterrupter.

It may be further pointed out that the development of a singular arc,such as are E, from a plurality of arcs such as A and B, will producelevels of arc voltage that are generally stable and free of excessivepeaks. This are voltage stability is primarily determined by theopposite and generally parallel spacing of the arc runners 17 and 22, sothat in conjunction with the concentric positioning of the tank 1, andthe insulating liner 15 when used, the maximum arc length is controlledwhile the arc is being extinguished. The generally opposed and equallyspaced spiral arc runners 17 and 22 are preferably designed to besubstantially free from major surface obstructions which might delay therunning of the arc terminals, and the short gaps therein are disposedout of register as noted hereinbefore.

The interruption time of the new and improved circuit interrupter of theinvention having the generally opposed spiral arc runners has been foundto be rapid. For example, in a test conducted to interrupt a DC. currentof 48,500 amperes at 700 volts, and using a tank containing hydrogen gasat a pressure about 20 times greater than atmospheric, the interruptiontime was .006 second and the developed arc was moved by the magneticforce fields, i.e., by the net tangential force, at an average speed ofapproximately 425 feet per second through the hydrogen gas.

A modification of the circuit interrupter of the invention is shown inFIG. 6. A partially shown metallic tank 50 and an inner liner 51 aresimilar to those components of the circuit interrupter previouslydescribed. Line terminals 53 and 54 extend generally axially into thetank t preferably from the same side of the circuit interrupter asshown. An upper spiral arc runner 56 is fixedly disposed as previouslydescribed within the tank 50 slightly above but generally surroundingthe inwardly extending line terminals 53 and 54. The upper spiral arcrunner 56 is suitably insulated from the tank by an insulator supportassembly 57. Additionally, the upper spiral arc runner 56 is maintainedin electrical continuity with the inwardly extending line terminal 53. Alower spiral arc runner 52 5 which is generally concentrio with the arcrunner 56, is pivotally secured to and maintained in electricalcontinuity with the inwardly extending line terminal 54 about a pivotalpoint or rotational axis 69. The lower spiral arc runner 59 is adaptedto be actuated about the rotational axis 60 by means of a suitablemechanical linkage represented by the member 62 which is actuated byexternal means, not shown. The member 62 is pivotally joined to runner59 at a point 62a which is relatively close to the axis 69*. Theinwardly extending line terminal 53 pivotally secures a radiallyextendingcontact bar 64 about a rotational axis or pin 65. A resilientmeans 66, for example, a spring or the like, is suitably positioned tourge the contact bar 64 to a normal position such as shown by FIG. 6. Acooperating contact 67 is maintained in electrical continuity with thelower spiral arc runner 59 on which it is located, and upon pivotalmovement of the lower arc runner about the rotational axis 60 to acircuit making position, as is shown in FIG. 7, the contact 67 willseparably engage the contact bar 64. Resilient means 66 assures a firmelectrical contact between contact bar 64 and contact 67.

Operatively, a line current will pass through the modification of thecircuit interrupter as shown by FIG. 6 when the lower spiral arc runner59 with the contact 67 thereon is arcuately moved to engage the contactbar 64 as shown by FIG. 7. When the lower spiral arc runner 59 and thecontact 67 are moved away from the contact bar 64 toward a. normalcircuit breaking position as tively.

shown byPIG. 6, -an F is drawn between'the respective contacts 64 andv67. In a manner similar to that previously described, the developed arcwill move radially outwardly to a position G where it touches the upperspiral arc runner 56 and is transferred thereto. The previouslydescribed tangential force again causes the arc G to move orbitallyalong the upper and lower spiral arc runners 56 and 59, and the arc isquickly extinguished as before. The proposed modification shown by FIGS.6 and 7 provides a mechanical arrangement wherein circuit interruptionis accomplished upon movement of the actuating member 6?. through only arelatively short distance, this distance being much less than the lengthof the gap formed between the separated contacts 64 and 67. FIG. 8 showsanother modification of the invention having a metallic tank 7 it,partially shown, similar to the tank previously described and shown byFIGS. 1 and 2. The metallic tank 70 encloses an upper spiral arc runner71 and a lower spiral arc runner 72 that are centrally positioned withinthe metallic tank 7 i) and spaced therefrom in a fashion similar to thatpreviously described and shown by FIGS. 1 through 4. The upper spiralarc runner 71 is maintained in electrical continuity with an incomingline terminal '73, while the lower spiral arc runner 72 is similarlymaintained in electrical continuity with line terminal 74.

An annular upper secondary arc runner 76 and an annular secondary arcrunner 77 are located in parallel, spaced relationship within themetallic tank 70 on the inner surface sheet or cylinder 79 that issimilar to the liner member 15 previously described and shown by FIGS. 1and 2. These secondary arc runners are interconnected by a plurality ofparallel resistance elements embedded in the sheet 79, such as theresistor 80 shown schematically in FIG. 8. The secondary runners 76 and77, as can be seen in FIG. 8, are separated by a distance less than thespacing between spiral runners 71 and 72 and are disposed medially withrespect thereto.

An upper terminal 82 and a lower terminal 83 of a developed arc K,similar to the developed are E previously described and shown by FIGS. 2through 5, touch the upper spiral arc runner 71 and the lower spiral arcrunner 72 respectively. In the modification of the circuit interruptershown by FIG. 8, the developed arc K extends radially outwardly underthe magnetic effect previously described and is then intercepted by thesecondary arc runners 76 and 77. This will divide the are into twoserially related distinct arclets L and M. Arclet L has terminals 84 and85 on the upper spiral arc runner 71 and the proximate secondary'arcrunner 76, respec- In similar fashion, arclet M has terminals 86 and 87on the lower spiral arc runner 72 and the proximate secondary arc runner77, respectively.

, Operatively, circuit current flowing between line terminals 73 and 74during the circuit interrupting process will pass in series through theupper spiral arc runner 71, arclet L, upper secondary arc runner 76,resistor 80, lower secondary arc runner 77, arclet M, and the lowerspiral arc runner 72. Current flowing through the resistor 8% results indissipation of system energy without appreciably heating the gas oratmospheric mixture confined within the metallic tank '70, and thistends to reduce the increase in internalpressure within the tank. Theresistor is positioned near the metallic tank wall 70 for rapid heatdissipation, thereby minimizing the temperature elevation of theconfined gas and the consequent increase of internal pressure due to theheating of this resistor. Thus, the modification of the invention asshown by 1 16. 8 enables a thinner metallic tank wall 70 to be usedwithout impairing safety of the overall circuit interrupter. V i

As will be evidenced from the foregoing description, certain aspects ofthe invention are not limited to the particular details of theconstruction illustrated. For example, the optional insulating liner maybe omitted,

dependent upon the final design parameters of the metallic tank.Further, it is contemplated that the spiral arc runner members, althoughshown in planes generally parallel to the plane of the stationarycontacts, could be equally spaced from and opposed to each other atsomething other than a parallel relationship to the plane of thestationary contacts. The primary consideration of the invention is toposition the spiral arc runners within the enclosing tank so that thelength of a developed arc is maintained relatively constant as it iscirculated by the magnetic force field until the arc is extinguished bythe atmosphere in the tank.

It is also contemplated that the particular circuit interrupterpreviously described can function as a device for arcing contacts only.Thus, separate main current carrying contacts may be positionedexternally of the interrupter tank so that the main contacts would beprotected from any damaging erosion caused by a developed arc.Therefore, while additional modifications and applications will occur tothose skilled in the art, it is intended that the appended claims shallcover such modifications and applications that do not depart from thetrue spirit and scope of the invention.

Having described the invention, what is claimed is:

1. A circuit interrupter comprising:

(a) a tank;

(12) a pair of line terminals extending into said tank;

(c) first and second stationary electric contacts disposed within saidtank in spaced relation to each other and insulated from the tank;

(d) means for electrically connecting said stationary contacts to saidline terminals, respectively;

(e) a movable bridging contact disposed separably to engage saidstationary contacts within said tank;

(1) a first arc runner member located adjacent to said stationarycontacts and insulated from said tank;

(g) a second arc runner member generally surrounding said bridgingcontact and insulated from said tank;

(11) means for electrically connecting said first and second arc runnermembers to said first and second stationary contacts, respectively; and

(i) actuating means for moving said bridging contact to establish anelectric arc in the tank;

(j) said arc runner members being positioned in opposition to and spacedfrom each other for receiving said arc and being so arranged that amagnetic field is developed therebetween in response to current flowingtherein for continuously moving the are along said members while the arcis being extinguished within said tank.

2. The circuit interrupter of claim 1 in which said tank containshydrogen gas.

3. The circuit interrupter of claim 1 in which said line terminals entersaid tank through a common wall thereof and extend interiorly ingenerally parallel directions.

4. The circuit interrupter of claim 1 in which said arc runner membersindividually define spiral surfaces.

5. The circuit interrupter of claim 4 in which the spiral surfaces ofsaid members are equidistantly spaced from each other and in which saidtank has a circular cross section which is concentric with said members.

6. The circuit interrupter of claim 5 in which the spiral surfaces ofsaid members curl in agreement with each other.

7. The circuit interrupter of claim 6 in which a liner member isdisposed adjacent to an inner wall of said tank, said are runner membersbeing encircled by said liner member which provides electricalinsulation between said members and said tank.

8. A circuit interrupter comprising:

(a) a tank containing an atmosphere;

(b) a pair of line terminals extending into said tank;

(0) first and second stationary electrical contacts disposed in a commonplane within said tank in spaced 10 relationship to each other andinsulated from the tank;

(d) means for electrically connecting said stationary contacts to saidline terminals, respectively;

(e) a movable bridging contact disposed separably to engage saidstationary contacts within said tank;

(j) actuating means for moving said bridging contacts normal to saidplane of the stationary contacts to draw an electric arc in the tank;

(g) a first arc runner member located adjacent to said stationarycontacts and insulated from said tank;

(h) a first bar member appended to said first arc runner member andelectrically connected to said first stationary contact;

(1') a second arc runner member generally surrounding said bridgingcontact and insulated from said tank, said second member being disposedin opposition to and equidistantly spaced from said first arc runnermember; and

(j) a second bar member appended to said second arc runner member andelectrically connected to said second stationary contact;

(k) said first and second bar members being arranged to position saidfirst and second arc runner members for receiving and limiting thelength of said arc.

9. The circuit interrupter of claim 8 in which said arc runner membershave spiral configurations, with the opposite ends of each arc runnerbeing spaced from each other by a relatively short gap.

10. The circuit interrupter of claim 9 in which the gap between ends ofone of said are runner members is out of register with the gap betweenends of the other are runner member.

11. The circuit interrupter of claim 9 in which said tank has a circularcross section which is substantially concentric with said are runnermembers.

12. The circuit interrupter of claim 11 in which said atmosphere ishydrogen gas.

13. A circuit interrupter comprising:

(a) a tank;

(b) first and second line terminals extending into said tank;

(0) a first spiral arc runner fixedly disposed within said tank andelectrically connected to said first line terminals;

(d) a first electrical contact associated with said first terminal;

(e) a second spiral are runner pivotally mounted within said tank andelectrically connected to said second line terminal, said second arcrunner being disposed in substantially concentric relationship withrespect to said first are runner;

(f) a second electrical contact located on said second arc runner forseparably engaging said first contact upon pivotal movement of thesecond arc runner; and

(g) means for moving said second arc runner to draw an electric arebetween said first and second contacts;

(it) said first arc runner being so positioned that the arc terminal onsaid first contact will transfer to said first runner, and said firstand second arc runners being so arranged that current flowing thereinproduces a magnetic field therebetween which interacts with said are topropel the arc continuously along said runners until the arc isextinguished.

14. The circuit interrupter of claim 13 in which said tank containshydrogen gas.

15. The circuit interrupter of claim 14 in which said tank has acircular cross section which is substantially concentric with said arerunners.

16. The circuit interrupter of claim 15 in which a liner member isdisposed adjacent to an inner wall of said tank to provide electricalinsulation between said arc runners and said tank.

'17. A circuit interrupter comprising: i

(a) a tank having a circular cross section;

(b) two electroconductive members fixedly disposed (c) a first pair ofelongated, generally circular arc runners disposed centrally within saidtank in substantially concentric relationship with said circular crosssection, each runner of said first pair being electrically connected atone end thereof to a different one of said electroconductive members andhaving its opposite end spaced from its one end by a relatively shortgap; a

(d) an insulating liner disposed adjacent to an inner wall of said tankto encircle said first pair of runners;

(e) a second pair of annular arc runners located in parallel, spacedrelationship adjacent to an inner surface of said liner, said secondpair of runners I being medially disposed with respect to the runners ofsaid first pair;

' ,(f) a plurality of resistance elements supported by said liner andelectrically connected in parallel between the runners of said secondpair; and

(g) contact means within said tank for establishing an electric arebetween the runners of said first pair.

18. The circuit interrupter of claim 17 in which said 5 first and secondpairs of arc runners are so arranged that said are will be interceptedby said second pair of runners for division into two serially relatedarclets between the proximately disposed runners of the respectivepairs.

19. The circuit interrupter of claim 18 in which said tank containshydrogen gas.

References Cited by the Examiner UNITED STATES PATENTS BERNARD A.GILHEANY, Primary Examiner.

5 ROBERT K. SCHAEFER, Examiner.

1. A CIRCUIT INTERRUPTER COMPRISING: (A) A TANK; (B) A PAIR OF LINETERMINALS EXTENDING INTO SAID TANK; (C) FIRST AND SECOND STATIONARYELECTRIC CONTACTS DISPOSED WITHIN SAID TANK IN SPACED RELATION TO EACHOTHER AND INSULATED FROM THE TANK; (D) MEANS FOR ELECTRICALLY CONNECTINGSAID STATIONARY CONTACTS TO SAID LINE TERIMINALS, RESPECTIVELY (E) AMOVABLE BRIDGING CONTACT DISPOSED SEPARABLY TO ENGAGE SAID STATIONARYCONTACTS WITHIN SAID TANK; (F) A FIRST ARC RUNNER MEMBER LOCATEDADJACENT TO SAID STATIONARY CONTACTS AND INSULATED FROM SAID TANK; (G) ASECOND ARC RUNNER MEMBER GENERALLY SURROUNDING SAID BRIDGING CONTACT ANDINSULATED FROM SAID TANK; (H) MEANS FOR ELECTRICALLY CONNECTING SAIDFIRST AND SECOND ARC RUNNER MEMBERS TO SAID FIRST AND SECOND STATIONARYCONTACTS, RESPECTIVELY; AND (I) ACTUATING MEANS FOR MOVING SAID BRIDGINGCONTACT TO ESTABLISH AN ELECTRIC ARC IN THE TANK; (J) SAID ARC RUNNERMEMBERS BEING POSITIONED IN OPPOSITION TO AND SPACED FROM EACH OTHER FORRECEIVING SAID ARC AND BEING SO ARRANGED THAT A MAGNETIC FIELD ISDEVELOPED THEREBETWEEN IN RESPONSE TO CURRENT FLOWING THEREIN FORCONTINUOUSLY MOVING THE ARC ALONG SAID MEMBERS WHILE THE ARC IS BEINGEXTINGUISHED WITHIN SAID TANK.